Recently, staple-carrying cartridges have been designed which eliminate the requirement for the complex gearing once needed in the powering of a surgical stapling instrument. With these cartridges, the output shaft or thrust bar of the powering instrument need only have rectilinear thrust capabilities. The staples are advanced by means designed into the cartridges themselves. In commonly assigned U.S. Pat. No. 3,618,842, the advancing pusher, integral with the cartridge, rotates a pair of staple-driving screws by means of cams formed in the rear portions of the screws. In commonly assigned U.S. Pat. No. 3,638,847, the staples are driven forward by the interaction of pairs of opposing ratchet teeth integral with the cartridge.
More recently, in commonly assigned U.S. Pat. No. 3,650,453, the staple-carrying cartridge includes a flexible belt moveably housed in the cartridge body. Staples are guided and advanced by association with spaced teeth on the flexible belt. The cartridge is equipped with an anvil integral with the cartridge body and a pusher which advances the staples and singly forms the same. Further improvements and modifications to the belt cartridge are disclosed in commonly assigned U.S. Pat. No. 3,717,294.
These prior cartridges are adapted to house staples which have a "U" configuration prior to being formed around the anvil. The pusher and associated anvil are then adapted to form the staples into a rectangular configuration in which the points of the staples abut. Although staples formed in this manner have proved satisfactory in practice, there are certain disadvantages associated with these staples, particularly when joining together disunited fascia. In particular, the points of the staples do not enclose as much fascia during the formation of the staples as desired. Moreover, in the final configuration, with the points of the staples abutting, the staples do not have as much resistance to being pulled apart as desired. For these and other reasons, it would be advantageous to have improved staples and an associated cartridge adapted to accept these staples which avoids the disadvantages mentioned above.
Accordingly, it is a broad object of this invention to provide a new staple design for stapling the disunited fascia or similar living tissue of a patient.
It is another object of this invention to provide a new staple design in which the points of the arms of the staple are widely spaced apart and enclose a large amount of fascia as the arms of the staple sweep through an arc during staple formation.
It is still another object of this invention to provide a new staple design in which the arms of the staple, after formation, resist being pulled apart.
It is yet another object of this invention to provide a staple-carrying cartridge which is adapted to accept the new staples.
Another object of this invention is to provide a staple-carrying cartridge which has improved means for advancing, forming and ejecting the staples.
These and other objects of the invention, as well as many of the attendant advantages thereof, will become more readily apparent when reference is made to the following description taken in conjunction with the accompanying drawings.